Water purification: meeting challenges within laboratory applications

Water is used as a reagent, sample preparation, blank preparation, solid-phase extraction, and more in various laboratory applications or laboratory analysis. There are various laboratories like a clinical laboratory, biomedical laboratory, pharmaceutical, environmental laboratory, biosafety laboratory, etc., use water for different purposes. Normal tap water cannot be used for laboratory purposes. It is important to understand the impact of contaminants on the water in laboratory applications.

Modern technologies have developed many rapid and automated instruments for the laboratories to perform complex testing techniques almost all of the techniques require water. Many research scientists have discussed how water quality impacts the accuracy and reliability of laboratory applications. It is important to monitor the quality of water according to standard guidelines by various organizations such as ASTM, CLSI, ISO. These water quality standards helped laboratories to use the right grade of water for their applications and enhance the accuracy of the critical applications.

This importance of consistent and reliable water quality requirements in the laboratory has led to the introduction of different water purification technologies. Using the water purified with these technologies has significant improvement in the accuracy of laboratory analysis. Here we discuss the challenges faced with different laboratory applications to ensure the right purified water.

Definition of Water Quality and Related Contaminants

Water quality has been defined by several organizations like ASTM, CLSI, ISO. The specifications of different grades of water may vary slightly between the water quality standards of different organizations.

CLSI recommends the pure water that is required for optimal laboratory tests. CLRW  ( Clinical Laboratory Reagent Water) is defined by CLSI as the minimum quality water suitable for clinical laboratory applications. CLSI replaces the Type 1 and Type 2 water with CLRW in most of the applications. Instrument feed water (IFW) specified by CLSI  can be used for autoclaving, water baths, and rinsing glassware. Special Reagent Water (SRW) specified by CLSI is used for specific applications like high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS), and molecular biology-based assays.

Generally, the lab purified water is classified based on the measurements of ionic purity (resistivity), Organic purity (TOC- Total Organic Carbon), bacterial level, and particulate level.

CLSI Specification for Reagent Laboratory Water

Water TypeApplication (Example)
CLRW (Clinical Laboratory Reagent Water)Most laboratory applications or methods; similar to types I and IIDefined as minimum quality for routine biochemistry assays
IFW (Instrument Feed Water)Immunoassay, molecular assays, HPLC, LC-MS, GC, microarray, IVF
SRW (Special Reagent Water)Autoclave use and washing require

Read more: Laboratory Water Purification Systems

The ASTM (American Society for Testing and Materials) established water quality specifications for reagent water as Type I, Type II, Type III, and Type IV.

Water Contaminants

There are many contaminants present in the water which affect the laboratory analysis and result in inaccuracy.  These contaminants interfere in the laboratory applications and result in the consequences of their presence  For example,

Particles And colloids

Particles and colloids present in the water may be soft or hard and will affect the laboratory application in many ways. It may block the nebulizer and prevent the effective spraying of solution into the flame of the AA (Atomic Absorption) assay. Particles and colloids may damage the High-Performance Liquid Chromatography (HPLC) pump and injectors. This in turn increases the system backpressure. 

Bacteria And Endotoxin 

Bacteria or its by-products such as nucleases, alkaline phosphatase, and pyrogens, can interfere with many molecular biology applications. The enzymes produced by bacteria, and nucleases endotoxin, RNases, DNases, and proteases speed up the hydrolysis of DNA and RNA and reduce the accuracy of the application. Endotoxin inhibits cell culture and reduces accuracy. Bacteria and its byproducts will affect the media pH and contaminate pure culture, prevent cell growth and affect IVF (In Vitro Fertilization).

Dissolved Gases

Gases such as oxygen, nitrogen, carbon dioxide, or chlorine get easily dissolved in the water. These gases form nubbles and interfere in the particulate counting and spectrophotometric measurements. The chlorine present in the water can have a bleaching effect in various stainings in histopathology.

Organic Contaminants

Organic contaminants present in the water interfere with spectrophotometric experiments, especially in UV absorbance. Organic contaminants absorb calcium and reduce the calcium present in the specimen. These organic contaminants increase the background in fluorescent assays and HPLC which in turn increases the background noise and enlarged peaks (ghost peaks). This contamination also deactivates enzymatic reactions and inhibits cell growth.

Inorganic contaminants

Inorganic Contaminants generally metallic ions act as a catalyst for chemical reactions. This ionic contamination increases blank signal in AA heavy metals such as lead, mercury, and Zinc are toxic to various cells in cell culture.

Methods of Water Purification

There are different methods of the water purification system laboratory to remove such contaminants from the water. The combination of these water purification technologies helps to remove all the contaminants to a negligible level and produces ultrapure water.

Water pretreatment technologies

  • Microporous depth filters
  • Activated Carbon (AC)- in pretreatment media

Major Water Purification Technologies

  • Reverse Osmosis (RO)
  • Ion Exchange (IX)
  • Electrodeionization(EDI)
  • Distillation 
  • Activated carbon
  • Microporous filters
  • Ultrafilters
  • Vent filters
  • Degassing membranes
  • UV light

Read more: Laboratory Water Purification Technologies | Their Advantages

These challenges met with laboratory applications with the presence of impurities in the water have driven the importance of the water purification system for the laboratory use. When it comes to the purity of water there are many misconceptions to select the different grades of water from Type 1, Type 2, and Type 3. 

These different grades of water from the laboratory water purifier, when stored in a container the purity of the water get affected at the point of use. Generally, the lab purified water from the water purification system for the laboratory use is commonly supplied in plastic bottles. If the plastic bottles are not manufactured and handled correctly it may contaminate the lab purified water stored with organic plasticizers or monomers especially when it is stored for a long time.

Once the lab purified water is open from the bottles and exposed to the air then the contaminants like bacteria, ionic and organic will get introduced into the water. In the case of ultrapure water due to its low resistivity level, it is highly reactive when exposed to the air and hence caution should be taken when storing water for later use.

Another important issue is the quantity of water required. The water requirement for the laboratory is large and hence the number of bottles required is significant. Alternative to bottled purified water is the water purification system for laboratory use. This water laboratory water purifier is often proven to be cost-effective over the long term. The initial investment and the maintenance of the lab water purification system lower the cost per litre when considering it for the long term. This lab water purification system reduces the impact of environmental contaminants since this can be used freshly at the point of use and eliminates the waste of water by storing.

There are different lab water purification systems available with different grades of purity. Depending on the level of purity the water purification system laboratory can be purchased. This laboratory water purifier provides you with the flexibility to change the water purification as needed over time.

Read more: Buying Tips - Water Purification Systems For Laboratory


The challenges faced with contaminants in the water are discussed and challenges faced in the bottled water and water storage in containers are also outlined. laboratory water purification price compared to bottled water lowers over a long time. Now choose the best water purification system laboratory with Lab Q. Get our expert’s advice for the better water solution in the laboratory.

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